The present invention pertains to medication dispensing devices, and, in particular, to a portable injector apparatus that permits a user to self-inject medicine such as insulin.
Patients suffering from diseases such as diabetes frequently must inject themselves with insulin solutions. To permit a diabetic to conveniently and accurately self-administer proper doses of insulin, a variety of insulin injector pens have been developed. These insulin pens are so named due to their general resemblance to a writing instrument in their elongated shape and overall length.
An insulin pen typically includes an insulin filled cartridge connected with a needle through which insulin may be injected into a user. Needleless insulin pens are also available. To inject a dosed quantity of insulin, the pen is maneuvered such that the tip of the needle is inserted subcutaneously into the user. Next, in order to move a plunger within the cartridge axially toward the injection needle to force insulin from the cartridge and out through the needle, a button or knob that projects from the distal end of the pen body is depressed and moved relative to the pen body. This knob is typically depressed in line with and toward the needle by a finger, such as the thumb, of the hand in which the insulin pen is being held. In order to so drive the knob, an axial force must be applied to the insulin pen knob, and unless a counteracting force is provided by the patient on the insulin pen body, the needle may be driven deeper into the patient""s body. Such a deeper needle penetration below the skin surface is undesirable as not only may it potentially result in a delivery of insulin intramuscularly rather than merely subcutaneously, but it also may cause a user to perceive greater pain or discomfort, which in turn may lead to anxiety by the user in performing insulin injections in the future.
One shortcoming of many existing insulin pens results from the infirmities of its potential user. Over time, many diabetics who self administer insulin via these insulin pens suffer a degree of feeling loss within their fingers as a result of the diabetes. Consequently, comfortably gripping an insulin pen sufficiently tightly at various times during its use to allow for proper operation may prove difficult. For example, one known insulin pen comprises a slender, cylindrical body and cap formed of stainless steel. The stainless steel surface of this model, as well as a textured stainless steel surface provided on an alternate, more colorful pen version, possesses a sufficiently low coefficient of friction so as to be relatively slippery to the grip under many operating conditions. As a result, the high squeezing forces with which pens of this type must be clenched within a user""s hand to supply enough of a frictional force on the cylindrical pen body to prevent it from slipping through the hand during plunger shifting associated with insulin injection may not be readily achievable by some users. Even if the required force can be applied by a given user, it would be desirable to reduce the necessary gripping force to decrease the effort required to be expended in using the insulin pen.
Grippability deficiencies with respect to some insulin pens also are manifested at times during their use other than injection. For example, separately gripping and then pulling apart a pen cap and body in order to remove the cap to expose the insulin delivering needle may be problematic for some users.
Thus, it would be desirable to provide a medication injecting apparatus that overcomes these and other problems of the prior art.
The present invention provides a medication delivery apparatus having a housing formed with a soft touch material to promote a ready and comfortable gripping by a user. Preferably, the soft touch material is secured over a more rigid substrate which forms the housing of the device. The medication delivery apparatus may be one of a variety of so-called pen devices including a reusable pen, a disposable pen, or a needleless pen. The apparatus may be designed and configured to deliver any appropriate medication including proteins and peptides such as insulin, human growth hormone, parathyroid hormone, glucagon, etc. The following detailed disclosure of a device for the delivery of insulin is merely illustrative of the present invention.
As used throughout this application, the term xe2x80x9csoft touchxe2x80x9d generally references the softer, more rubbery and less slick feel characteristics of a material as perceived by a user in comparison to the feel of other materials such as plastics and metals conventionally employed as the exterior housing of medication delivery apparatuses. Such soft touch materials may be defined in a number of ways. For example, a soft touch material includes a material that has a coefficient of friction greater than that of the substrate material over which the soft touch material is secured. In addition, the soft touch material may be identified as being softer than the underlying substrate as measured on the Durometer A and/or Durometer D scale. Also, the thickness of the material can be determinative in promoting a ready and comfortable gripping by the user. For example, certain soft touch materials may appear softer due to the fact that they are applied to the substrate at a greater thickness.
In one embodiment, the soft touch material comprises a thermoplastic elastomer, such as a styrene-butadiene-styrene (SBS) block copolymer, or a styrene-isoprene-styrene (SIS) block copolymer. Other suitable thermoplastic elastomers include polyurethanes and copolyesters and blends of ethylene-propylene copolymers with polypropylene. In addition to thermoplastic elastomers, the soft touch material may comprise other synthetic elastomers such as polyisobutylene, butyl rubber, and polychloroprene. The soft-touch material may include other polymer materials that result in a better and more comfortable grip by the user. Other general categories of soft touch materials, which may or may not overlap with those set forth above include thermoplastic rubbers, polyester or polyurethane elastomers, vinyls, and urethanes.
The present invention further provides a medical delivery apparatus having a housing that is ergonomically contoured to furnish an abutment engageable by a portion of the hand gripping the apparatus during its operation. The abutment serves as an axial stop against which a user may conveniently apply an axial force on the apparatus to counteract the force applied to administer the injection of medication through the needle of the apparatus. In this aspect of the present invention, the housing may or may not include a soft touch material.
In one form thereof, the present invention provides a medication delivery apparatus including a housing elongated in an axial direction, a container of medication mounted to the housing, an outlet in flow communication with the container to receive medication forced therefrom, and a drive assembly including an actuator movable relative to the housing from a first position to a second position. The drive assembly is adapted to interact with the medication container to deliver medication from the container and through the outlet upon movement of the actuator from the first position to the second position. The exterior periphery of the housing includes a projecting abutment for digit engagement which is axially arranged along the housing length for abutting contact by a first digit of a hand of a user when the housing is grasped within the user""s hand such that a second digit of the hand of the user may operate the actuator. The abutment includes an ergonomically curved surface contoured to fit the user""s first digit.
In another form thereof, the present invention provides a medication delivery apparatus including a housing elongated in an axial direction and comprising a length extending between first and second axial ends. The housing further includes a generally tubular base and a gripping layer covering at least a portion of the base and forming an exterior surface of the housing. The gripping layer is formed from a material that is softer than the material used to form the portion of the base covered by the gripping layer. The apparatus also includes a container of medication mounted to the housing, an outlet in flow communication with the container to receive medication forced therefrom, a drive assembly, and a dosage member. The drive assembly includes an actuator movable relative to the housing from a first position to a second position and is adapted to interact with the medication container to deliver medication from the container and through the outlet upon movement of the actuator from the first position to the second position. The dosage member is operable to control a quantity of medication delivered from the container by the drive assembly.
In still another form thereof, the present invention provides a housing for a medication delivery device including a medication delivery outlet, a medication filled chamber, and a drive assembly for forcing medication from the chamber through the outlet. The housing includes a body comprising at least one opening through which the drive assembly extends to enable its control, and a cap comprising an interior cavity sized to cover the outlet when the cap is connected with the body. The exterior periphery of the body comprises a soft-touch construction for facilitating gripping of the body by a user upon delivery of the medication.
One advantage of the medication injecting apparatus of the present invention is that the soft touch construction of its periphery results in an instrument which feels comfortable in the hand of a user and which provides a more easily grippable surface.
Another advantage of the present invention is that the laterally projecting, contoured portion of the housing provides a stop surface against which a hand abuts when the apparatus is held for injection, thereby aiding users with limited gripping abilities to more easily resist axial forces applied to the apparatus during a plunging stroke used to effect medication injection.
Still another advantage of the present invention is that the soft touch construction of both the housing body and cap makes it easier for a user to uncap the apparatus to expose the needle for injection.